Induced pluripotent stem cells (iPS cells) would be useful for transplantation therapies for various diseases and are expected to be applied to regenerative medicine. It has been reported in recent years that iPS cells can be generated by selecting cells expressing Fbx15 gene from somatic cells such as fibroblasts and hepatocytes in which Oct3/4 gene, Sox2 gene, Klf4 gene, and c-Myc gene have been introduced and expressed (see, e.g., WO 2007/069666; Takahashi K, Yamanaka S. (2006). “Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors”. Cell 126: 663-676; Takahashi K, Okita K, Nakagawa M, Yamanaka S. (2007). “Induction of pluripotent stem cells from fibroblast cultures”. Nature Protocols 2: 3081-3089; Aoi T, Yae K, Nakagawa M, Ichisaka T, Okita K, Takahashi K, Chiba T, Yamanaka S. (2008). “Generation of pluripotent stem cells from adult mouse liver and stomach cells”. Science 321(5889): 699-702).